Field of the Invention
The present invention relates to heavy duty pneumatic tires, and in particular, relates to a heavy duty pneumatic tire that may exhibit an excellent wet performance as well as on-snow performance.
Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2005-280457 discloses a heavy duty pneumatic tire including a tread portion provided with a plurality of tread blocks separated by circumferentially extending main grooves and lateral grooves. Each tread block is provided with two axially extending sipes to divide the block into three portions which includes a pair of end portions and a middle portion therebetween. Each edge of the portions of the block may produce high friction force against icy road by scratching the road. Furthermore, each of the end portions of the block includes a projected portion that protrudes outwardly in a block-width direction from the middle portion. The respective projected portions may increase traction on snowy road by shearing a snow-column compressed in the main groove.
Unfortunately, since the respective projected portions are located on the same side and closely in the circumferential direction of the tire, the space between adjacent projected portions tends to be clogged up with snow during traveling. This may cause a problem of deteriorating of on-snow performance as well as deteriorating of wet performance.